The invention relates in general to the field of hybrid III-V on silicon laser devices.
Silicon photonics relates to applications of photonic systems, wherein silicon is used as an optical medium. The fact that it allows the integration of the photonic functionality, while leveraging know-how with silicon and its mass fabrication compatibility makes it a very attractive technology platform.
Yet, the indirect bandgap of silicon makes it a poor light emitter. Therefore, to build on-chip laser sources, several research groups have proposed a hybrid integration of III-V materials on silicon photonics structures, as for instance described in “Hybrid III-V on silicon lasers for telecommunication applications”, by Marco Lamponi, Université Paris Sud-Paris XI, 2012 <NNT: 2012PA112039>, <tel-00769402>, see https://tel.archives-ouvertes.fr/tel-00769402/.
In such laser sources, a single-mode operation is desired as this increases the efficiency and modulation bandwidth, as well as the output power of the fundamental (or the desired) mode. Single-mode operation of hybrid III-V on silicon lasers can for instance be achieved, based on, e.g., distributed feedback (DFB) laser architectures, which make it possible for the device to lase on a single longitudinal mode. Other laser architectures that can be contemplated for this purpose are, e.g., ring resonator lasers, arrayed waveguide grating lasers or sampled grating, distributed Bragg reflector (DBR) lasers. Often though, the cross section of such laser devices allows for higher-order transverse modes.